Combined inductor and worksupporting means



Dec. 4,1951 SEROTA 2,577,487

COMBINED INDUCTOR AND WORKSUPPORTING MEANS Filed Feb. 5. 1949 2SHEETS-SHEET 1 Patented Dec. 4, 1951 COMBINED INDUCTOR AND WORK-SUPPORTING MEANS Rudolph M. Serota, Milwaukee, Wis., assignor toAllis-Chalmers Manufacturing Company, Milwaukee, Wis., a corporation ofDelaware Application February 5, 1949, Serial No. 74,784

4 Claims. 1

This invention relates in general to improvements in means forinductively heating a workpiece, and in particular to improved means forheating and for releasably holding a workpiece.

A principal object of the present invention is to provide an improvedheating inductor in which the workpiece to be heated is releasablysupported within and by the inductor.

Another object of the invention is to provide an improved heatinginductor which can be divided and in which the workpiece to be heated isreleasably supported within the inductor.

Another object of the invention is to provide an improved heatinginductor which can be divided and in which a workpiece to be heated isreleasably supported within the inductor by a divisible portion of theinductor.

Another object of the invention is to provide an improved heatinginductor which can be divided and in which a workpiece held by theinductor for heating is released upon dividing the inductor.

Other objects will appear as the description proceeds.

The novel features of the invention and how the objects are obtainedwill be apparent from this specification and the accompanying drawingsshowing several embodiments of the invention and forming part of thisspecification and all the novel features are intended to be pointed outin the appended claims.

In the drawings:

Fig. 1 is a plan view of an induction device, or oven, as it willhereinafter be referred to, embodying the invention;

Fig. 2 is a side elevation of the induction oven shown in Fig. 1, aportion of the side wall and part of the electrical contacts thereofbeing broken away to reveal the divided structure of the heatinginductor;

Fig. 3 is a front elevation of the induction oven of Fig. 1, a portionof the reinforcing structure thereof being broken away to reveal acooling duct for the inductor;

Fig. 4 is a side elevation of an alternative embodiment of the inductionoven shown in Fig. 1; and

Fig. 5 is a section taken on the line VV in Fig. 1 showing the contactmeans for completing the electrical circuit through the inductor.

The invention illustrated in Figs. 1 to 5 can be embodied in many typesof induction ovens having divisible inductors of various shapes, but forpurposes of exemplification, the invention has been embodied in aninduction oven having 2 a divisible, single-turn,parallelepipedous-shape inductor.

Referring to Figs. 1 and 2 in which similar parts are identified by thesame reference characters, the oven here shown for inductively heating aworkpiece is constructed in the following manner.

A plate ID of insulating material having a centrally disposed opening II therein provides a base for a pair of upward-extending,parallellydisposed, spaced side walls 12, also of insulating material.The side walls 12 are joined at their forward ends by atransversely-disposed, reinforcing bar l3 of insulating material, and attheir rearward ends by a transverse wall M likewise of insulatingmaterial, the connection between the walls being made by means of screws:5.

The base l0 and walls l2, I4 together form an oven box within which adivisible, parallelepipedous or box-type inductor I7 is so positionedthat the inductor winding is sunk below the side walls l2, leaving onlythe reinforcing structure, cooling structure, and current leads,hereinafter described, extending above.

The inductor IT, as hereinbefore mentioned, is preferably shaped like aparallelepiped-one having the front and rear faces open-and is woundusing a ribbon conductor of comparative thinness and large transversewidth. As best shown in Figs. 1 and 2, the inductor I! comprisesessentially a first or fixed portion, and a second or movable portion,described as follows.

The fixed portion of the inductor l'i comprises first and secondbilaterally-symmetrical, conductor elements i 8, having respectivecoplanar segments l9 defining the top of a parallelepiped, andrespective depending side segments 2!) defining the sides of theparallelepiped. In order to lend rigidity to the fixed portion of theinductor H, the coplanar segments i8 are provided respectively with aplurality of reinforcing ribs 2i extending along the outside surface ofthe segments IS in the direction of the inductor turn, i. e., parallelto the transverse rear wall i i.

The depending side segments 20 extend in (:0- parallel relationrespectively adjacent to but spaced from the side walls !2, the spacingbeing effected by spacer pads 23 respectively inserted between thesegments 20 and the side walls E2. The conductor elements l8 aresupported in fixed position relative to the oven box by a plurality ofbolts 24 which pierce the side walls l2 and spacer pads 23 to threadinto the conductor segments 20.

The movable portion of the inductor comprises a third conductor'element,or, as it will hereinafter be referred to, a dump gate 25, engageablewith the side segments 29 of the first and second conductor elements l8,the dump gate being pivotally connected to the side walls of the ovenbox by hinge pins 25 and swingable vertically about a transverse axisthrough the pins 25. In order to provide additional bearing surface forthe hinge pins ZGand also to prevent wear of the side walls 12,apertured bosses 27 are respectively positioned adjacent the outsidesurface of the side Walls 12.

The dump gate 25 has a planar'conductive segment 28 defining the bottomof the parallelepiped and extending parallel to the coplanar segments 19of the first and second conductor elements it.

The planar segment 28 has the dual function of passing current throughthe dump gate 25 and providing a support for sustaining-workpieces,

not shown, within the inductor ii. In order to impart structuralrigidity to the dump gate '25 and reinforce the planar segment 23 in itssupporting function, a plurality of reinforcing ribs 25 are providedextending transversely of the oven box along the underside of the planarsegment 25.

The reinforcing ribs 2% lie between and at right angles to a pair ofside supporting arms 3% extending along either side of the dump gate 25parallel to the side Walls l2. The arms 3! are respectively providedwith upward-extending ears 32 and downward-extending cars 33. Theupward-extending cars '52 are ierced to respectively receive inn-onrotatable engagement the hinge pins 25. The downward-extending ears33 are likewise pierced to respectively receive bolts 35 for securing anoperating handle 35 in fixed position between the ears 33. The handle 36provides the means by which an operator can grasp the dump gate 25 toswing it vertically about the hinge pins 25.

Supported on the planar segment 28 of the dump gate 25 is a flat tray 38adapted to be slid into and out of the inductor I! when the dump gate 25is in the position shown in solid lines in Fig. 2. The tray 33 is madeof insulating material and provides the direct supporting surface uponwhich workpieces, not shown, may be deposited for heating by theinductor ll. The tray 38 has a handle 35 which extends outward from theoven boxand also has a pair of parallelly extending guides secured toits upper surface,

the function of the guides 45 being to forestall any movement oftheworkpieces toward the side segments 25 of the inductor ll. The tray38 is prevented from sliding out of the inductor ii, When the dump gate25 is in the position shown in broken line in Fig. 2, by retainingfingers 4! which are secured to the tray 33 and engage the foremostreinforcing rib 29 of the dump gate 25. I

Means for retaining the dump gate 25 in mechanical engagement with thefixed portion :8 of the inductor il when the dump gate 25 is swungupward'to the position shown in solid lines in Fig. 2 comprisesreleasable retaining means noid 55. Upon energization of the solenoid dby means not shown, the bolt 45 is retracted allowing the dump gate 25to swing downward under the influence of gravity and the force exertedby bias springs 52 respectively surrounding the hinge pins 25.

Means for effecting an electrical connection betweenthe dump gate 25andthe fixed portion i3 of, the inductor it comprises, asshown in Figs.2 and 5, longitudinally-disposed bar contacts 53 secured respectively toeither side of the dump gate 25 as by brazing, and wiping contact fingerassemblies. 54 bolted respectively to conductive pads 54' mounted on theside segments 25, the contacts 53 and wiping finger assemblies 55forming a releasable electrical connection.

- lS'of the inductor-H, the first bus bar 55 being secured to thecoplanar segment is of the first conductor element 18, and the secondbus bar 55 being secured to the coplanarsegment it of the secondconductor element it, the respective connections being effected bybrazing or the like.

A source of alternating current-the source being of any suitable typeand conventionally represented in the drawing of Fig.2 as a synchronousgenerator 55-providesthe means for energizing the inductor ll. Thegenerator 55 is connected to the inductor ll through the bus bars 55 andthe energization of the generator is controlled by a circuit breaker 5 1in the field circuit 58 of the generator 55. Control of the fieldcircuit breaker 57 is effected by means of an auxiliary circuit whichincludes a second circuit breaker 59 and an interlocking means tomounted on one of the side Walls 12 of the oven box below the hinge boss21.

fhe interlocking means 55 comprises a pair of contacts 6i that arenormally open when the dump gate 25 is tilted to the position shown inbroken line in Fig. 2. When the gate 25 is swung upward to the positionshown in solid line in Fig. 2, in which position the gate 25 iselectrically connected to the fixed portion [8 of the inductor IT, aprojection 62 on the depending ear'33 of one of the side arms 3! engagesa button 53 on the interlocking means 65 and closes the contacts 5%.Closure of contacts 5'! permits the auxiliary circuit to be manuallyclosed, as by manually closing in the second circuit breaker 59, whichbreaker then assumes exclusive control of the auxiliary circuit as longas the gate 25 is engaged. When the circuit breaker 59 is closed, aholding-in coil 59 takes over-the tripping switch 5i thereof having beenpreviously closed---and retains the breaker in closed position as longas the auxiliary circuit remains energized through the interlockingmeans 55. The purpose of the interlocking means 55 is to permitenergization of the generator 55 after conductive engagement of the dumpgate 25 with the fixed portion i the inductor I1, and to preventenergization of the generator 56 and the inductor 17 when the gate 25 istripped to assume the position shown in broken line in Fig. 2.

of the inductor H to the conduit 68 of the dump gate 25.

The flow of cooling fluid through the cooling means of the inductor I!may be traced as follows. Cooling fiuid from a source, not shown, may beintroduced through a first connecting nipple B9 to the duct 65 in thefirst bus bar 55, from Where it flows to the conduit 61 in the firstconductor element It. From the first conductor element i3, fluid isconveyed by one of the flexible hoses 6b to the conduit 68 in the dumpgate 25. The fluid circulates around the dump gate and then is returnedby a second flexible hose 6% to the conduit 5'! in the second conductorelement iii, from which the fluid flows through the duct in the secondbus bar 55 and out a second connecting nipple 69. It will be apparentupon referring to Fig. 1 that the conduit 61, B8 is so connected andarranged with respect to the inductor portions as to provide foreffective cooling of the inductor i1 during periods of energization.

Having described the structure of the induction oven incorporating oneembodiment of the invention, it is now meet to describe the operation ofthe oven and how a workpiece to be heated is releasably held therein.

The oven may be charged by removing the tray 38, wholly or partially,and placing one or more workpieces on the tray 33, then sliding the tray38 back in the oven; or, the oven may be charged by simply inserting theworkpieces within the inductor i? so as to have them rest upon the tray38. The tray 38 and dump gate 25 will occupy at the time of charging theposition shown in solid line in Fig. 2. After the oven is charged theinductor ll is energized from the source of high frequency current 56,and the inserted workpieces heated by induction. If it is desired toheat only one side of a workpiece the insulated tray 38 may be dispensedwith and the workpiece may be placed directly on the surface of theplanar segment 28 of the dump gate 25. Upon energization of the inductorI? by manually closing the circuit breaker 59, the side of the workpiecethat is touching the conductive segment 2% of the gate 25 will remaincool while the opposite side of the workpiece will become hot under theaction of the induced currents.

Following the heating of the workpieces, the

inductor ii is deenergized by opening th switch 5i to trip the breaker59 and cause deenergization of the generator Eli. The dump gate 25 isthen tripped by energizing the solenoid 50, the plunger d9 moving upwardand retracting the bolt to release the gate 25. Upon release, the gate25 swings vertically downward about the hinge pins 25 under theinfluence of gravity and the force exerted by the biasing springs 52.The tripping of the gate 25 opens the contacts ti, preventing theauxiliary circuit from being closed through the breaker 55, therebypreventing energization oi the generator 56.

Although the biasing springs 52 may not be necessary with allembodiments of the invention it has been found that the electricalcontacts 53, E i may exert a frictional resistance greater than thegravitational attraction on the dump gate. When this condition existsbiasing springs such as the springs 52 shown in Fig. 1 are necessary ifmanual manipulation of the dump gate 25 to the releasing position is tobe avoided.

After being tripped, the dump gate 25 moves to the position shown inbroken line in Fig. 2, releasing the workpieces from the inductor, andallowing them to slide from the tray 38 through Referring now to Fig. 4,an alternative embodiment is shown in which the tray is wholly supportedby the oven box when the tray is within the closed inductor, ascontrasted with the embodiment shown in Fig. 2 in which the tray issupported by a movable portion of the inductor. In the alternativeembodiment of Fig. 4, in which parts similar to like parts in the firstdescribed embodiment are designated by the same reference numerals, abase plate [0 similar to the base plate Ii) of Fig. 2 supports a pair ofside walls 12 and a transverse rear wall [4. The oven box formed by thethree walls l2, I4 is similar to the oven box of the first embodiment.An inductor I? having a fixed portion [3 similar to the fixed portionshown in Fig. 1 is sunk within the oven box and retained therein in asimilar manner.

The movable portion of the inductor is pivotally connected to the sidewalls by hinge pins 26, only one of which is indicated in Fig. 4, and isswingable in a vertical direction similar to the movement of the dumpgate 25 in the first embodiment, the movable portion herein comprising arectangular-shape dump gate 12 having a :planar conductor element 28 onthe upper side thereof. Electrical connecting means 53, 54 similar tothe electrical contacts hereinbefore described in connection with theembodiment of Fig. 5, are fastened to the fixed portion l8 of theinductor and to the dump gate 12 for carrying current between the fixedand movable portions upon engagement of the two.

A workpiece-supporting tray 13 extending parallel to and above the dumpgate 72 is pivotally connected to the side walls by hinge pins 74, onlyone of which is shown in Fig. 4. A pivoted link 1'5 joins the tray '13and the dump gate 72 and provides for a parallel motion of the tray 73and gate 12 upon movement thereof. Releasable means ll for sustainingthe gate 72 and tray 73 in charging and operating position, as shown inFig. 4, is mounted on a pad 18 on the rear wall. The releasable means 71comprises spring-biased bolts 79 adapted to slide in openings in therear wall M for engagement respectively with the tray 13 and dump gate72. The bolts 19 are fastened together for simultaneous movement bymeans of a slidable yoke connected to a bell crank 4?.

The bell crank 47 is in turn connected to the plunger 49 of a verticallydisposed solenoid 5G in the same manner as hereinbefore described inconnection with the embodiment of Fig. 2. Energization of the solenoid50 causes retraction of the bolts 79 allowing the gate 72 and tray 73 tosimultaneously swing downward, dumping any workpiece which may be on thetray 73 through the opening II in the base plate 10.

The tray 73 may have a second tray 8|, the counterpart of the removabletray 38 of the first embodiment, which tray 8| is similarly held inposition, when the tray 13 tips, by means of a plurality of lugs 82engaging with the tray 13, only one of the lugs 82 being shown in Fig.4. Thus the charging of the oven of the alternative spams? functionalutility in other types or shapes of in- 1 ductor-s. And it should beunderstood that the invention of the appended claims is not limited tothe exact details of design and construction described herein, forobvious changes and modifications within the scope of the claims will beapparent to those skilled in the art.

It is claimed and desired to secure by Letters Patent:

'1. A current-carrying :coil for inductively heating a workpiece,comprising first and second planar conductors having relatively parallelside portions depending therefrom, a third planar conductor having aplurality of contact surfaces, said third conductor being movable towardand away from said first and second conductors, means for effectingengagement of said third conductor with said first and second conductorsupon movement of said third conductor toward said first and secondconductors including a plurality of depending contact fingers connectedto each of said portions 'for electric engagement with said contactsurfaces upon movement of said third conductor toward said first andsecond conductors and including means for retaining said third conductorin engagement'with said first and second conductors, insulator meanscarried by said third conductor for releasably' supporting saidworkpiece in heating position within said coil, and releasable means foreffecting withdrawal of said third conductor from engagement with saidfirst and second conductors to release and drop said workpiece from saidcoil.

2. A current-carrying coil for inductively *heating a workpiece,comprising first and second planar conductors having relatively parallelside portions depending therefrom, a third planar conductor having aplurality of contact surfaces, said third conductor being movable towardand away from said first and second conductors, means for efiectingengagement of said :third conductor with said first and secondconductors upon movement of said third conductor toward said first andsecond conductors includin 2 5 1 111- rality of depending contactfingers connected to each of said portions for electric engagement withsaid contact surfaces upon movement of said third conductor toward saidfirst and second conductors and including releasable means for retainingsaid third conductor in engagement with said first and secondconductors, means carried by said third conductor for releasablysupporting said workpiece in heating position within said coil, andreleasable means for efiecting withdrawal of said third conductor fromengage ment with said first and second conductors to release and dropsaid workpiece from said coil.

3. In an induction oven for heating a workpiece the combination of apair of insulated side walls enclosing at least a portion of aparallelepipedous-shaped inductor, said inductor comprising mutuallyengageable first and second portions, said second portion comprising astructure hingedly supported on said side walls for swingable movementand biased to a disengaged position relative to said first portion,means associated with said second portion for supporting the work-pieceabove said second portion in insulated relation therewith, a pluralityof relatively engageable electric contacts associated with said firstand second portions for electrically connecting said portions uponmutual engagement thereof, means for retaining said second portion inengagement with said first portion when said second portion is swungfrom said disengaged position into an engaged position with said firstportion, and releasable means for effecting movement of said secondportion from said engaged position to said disengaged position torelease and drop said workpiece from said oven.

4. In an induction oven for heating a workpiece the combination of apair of insulated side walls enclosing at least a portion of aparallelepipedous-shaped inductor, said inductor comprising mutuallyengageable first and second portions, said second portion comprising astructure hingedly supported on said side walls for swingable movementand biased to a disengaged position relative to said first portion,means associated with said second portion for supporting the work-pieceabove said second portion, a plurality of relatively engageable electriccontacts associated with said first and second portions for electricallyconnecting said portions upon mutual engagement thereof, means forretaining said second portion in engagement with said first portion whensaid second portion is swung from said dis engaged position into anengaged position with said first portion, and releasable means foreffecting movement of said second portion from said engaged position tosaid disengaged position to release and drop said workpiece from saidoven.

RUDOLPH M. SEROTA.

REFERENCES CITED The following references are of record in the file ofthis patent:

